But Ron Avi Astor, a professor at the University of Southern California, who has carried out research into mass shootings and violence, said Eminem and other artists might need to re-evaluate the way they present their performances.

"One of the issues that comes up is that, he's been doing it for many years and so have others, but it has different meaning now," Astor told Canada's CBC News.

"Artists need to ask what kind of responsibility they have when the norms of the culture change to the point that people are actually afraid of being shot."

He added: "They could warn the crowd or they could not do [the song]."